This invention related to pavilions, herein called "vaulted shelters", which consists of a covering of flexible membranous material supported by a number of arches of which the structure shown in the Fritsche U.S. Pat. No. 2,797,696 dated July 2, 1957 and the Brogren U.S. Pat. No. 2,225,972 dated Dec. 24, 1940 are examples. Particularly, the invention relates to membrane shelters of this type which are made up of similar frame units, for a modular effect, to support the flexible membrane cover as illustrated and described in my applications listed above.